1. Field of the Invention
The present invention relates to a zoom lens system and an electronic imaging apparatus using the same.
2. Description of Related Art
In the digital camera market, while there is a tendency for further miniaturization and a higher zoom ratio, there also is an increased demand for a higher definition (higher picture quality). One way to obtain a higher definition is to, for example, use an image sensor (image pickup device) that has a large APS size. In an SLR camera, the image sensor is large, so that a high definition image can be achieved, however, since the overall camera system is large and heavy, demands for further miniaturization cannot be met. In recent years, a so-called “mirrorless” SLR camera has been proposed in which the quick-return mirror, which is a major characteristic feature of SLR cameras, is removed and does not use an optical finder system; however, it cannot be said that such mirrorless SLR cameras achieve sufficient miniaturization. Furthermore, lens-shutter zoom lens systems which pursue miniaturization have also been proposed, however, the incidence-angle of light that is incident on the imaging surface is not sufficiently perpendicular to the imaging surface (i.e., has poor telecentricity), so that use of such lens-shutter zoom lens systems with a digital imaging sensor is not realistic.
Examples of zoom lens systems of the related art are disclosed in Japanese Unexamined Patent Publication Nos. 2001-290076, 2002-221660 and 2009-25534.